CinCor Pharma is clinging to subgroup analysis despite its mid-stage hypertension study missing its primary endpoint in hopes of advancing the candidate to a phase 3 trial.
Investors seemed less convinced, sending CinCor’s shares plummeting 43% in the opening minutes of trading on Monday to $14.80 from a Friday close of $26.53.
The phase 2 HALO trial was evaluating the efficacy and safety of a highly selective aldosterone synthase inhibitor called baxdrostat in 249 patients with uncontrolled hypertension who were already taking up to two blood pressure medications at the maximally tolerated doses.
Neither the 0.5 mg, 1 mg or 2 mg baxdrostat doses led to a statistically significant reduction in seated systolic blood pressure (SSBP) across the study population after eight weeks when compared to placebo. In fact, the doses led to adjusted SSBP reductions of just 0.8, 0.1 and 3.8 mmHg, respectively.
However, the biotech was keen to point out that a pre-specified subgroup analysis of 116 non-Hispanic patients did see a 12.6 mmHg reduction in SSBP at the 2 mg dose. While this subgroup comprised just 46% of the trial’s participants, it represents up to 89% of the hypertensive population in the U.S., the company said.
“While we still need to learn more about the factors driving different responses in our pre-specified subgroup analyses, it is clear that baxdrostat generated double-digit SBP reductions in study subgroups, which include Black/African American patients, representative of approximately 81-89% of the hypertensive population of the U.S.,” said CinCor Chief Medical Officer Mason Freeman, M.D., in the release.
The company plans to combine the Halo data with the findings from its BrigHtn study of treatment-resistant patients when it talks to the FDA about entering a phase 3, Freeman added.
“The results of the two phase 2 trials, involving over 500 patients of diverse backgrounds, enable us to maintain our previously announced plans to meet with the FDA in January 2023 at an end-of-phase 2 meeting to discuss our phase 3 program plans,” CinCor CEO Marc de Garidel said in the release Nov. 28. “Following that meeting, we anticipate initiating our pivotal phase 3 trials in the first half of 2023.”
While two patients reported serious adverse events in the HALO trial, neither was considered to be related to baxdrostat. Three cases of moderate hyperkalemia, a term for high potassium levels, were reported, but none led a patient to discontinue the study, the company noted.